Cassiopeia and Andromeda Galaxy in the Air Glow

This serene view, captured on the great lake Alqueva, near the “Ermida de São Pedro” in Mourão, one of the regions belonging to the Dark Sky Alqueva Reserve, we find several scientifically interesting things. In the left top corner of the image, we could find the Cassiopeia constellation and below the double cluster NGC 884 and 869. Almost in the center image, is clearly visible the great Andromeda Galaxy M31, in Andromeda constellation, the neighbor of Pegasus. Above the Alqueva Lake, is visible the strong presence of Air Glow (Atmospheric Chemiluminescence) , the further thing I have seen similar to an Aurora, with yellow light, by emissions from sodium atoms in a layer at 92 km. Above it, we could see the green light from oxygen atoms in a layer 90-100 km high. This emission layer is clearly visible from earth orbit.